package day14;

import java.io.*;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

//用户系统
public class AccountSystem {
    static Scanner sc = new Scanner(System.in);
    static List<Account> list = new ArrayList<>();

    public static void main(String[] args) {
        one();
    }

    public static void one() {
        while (true) {
            System.out.println("********XXX系统********");
            System.out.println("1.登录");
            System.out.println("2.注册");
            System.out.println("3.退出");
            System.out.println("*****请输入编号*****");
            int n = sc.nextInt();
            switch (n) {
                case 1:
                    login();
                    break;
                case 2:
                    reg();
                    break;
                case 3:
                    return;
            }
        }
    }

    //如果第一次登录成功，可以记录缓存(登录成功的记录)
    //如果下一次再登录，还是相同的账号(可以不输入密码，直接免登录)
    //缓存的记录 一直存在30秒失效
    public static void login() {
        System.out.println("请输入你的账号");
        String account = sc.next();
        //通过缓存验证是否登录过 ==>two()
        Account acc = checkCookie(account);
        if (acc != null) {
            two(acc);
            return;
        }
        System.out.println("请输入你的密码");
        String password = sc.next();
        for (Account a : list) {
            if (account.equals(a.username) && password.equals(a.password)) {
                System.out.println("是否保存本地缓存y/n,30秒内免登录");
                String yn = sc.next();
                if ("y".equals(yn)) {
                    addCookie(a);
                    //场景可周期定长池  30S首次延迟功能

                }
                two(a);
                return;
            }
        }
    }



    public static Account checkCookie(String account) {
        try (BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("d://io//cookie.txt")))) {
            String msg = br.readLine();
            //将账号加密后和之前保存加密信息 匹配是否一致
            if (msg != null && msg.equals(md5(account))) {
                for (Account a : list) {
                    if (a.username.equals(account)) return a;
                }
            }
        } catch (FileNotFoundException e) {
            System.out.println("首次登录");
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
    public static String md5(String msg) {
        StringBuilder hexString = null;
        try {
            // 获取 MessageDigest 类的实例，指定算法为 MD5
            MessageDigest digest = MessageDigest.getInstance("MD5");
            // 对字符串进行加密
            byte[] encodedHash = digest.digest(msg.getBytes());
            // 将加密后的字节数组转换为十六进制字符串
            hexString = new StringBuilder();
            for (byte b : encodedHash) {
                String hex = Integer.toHexString(0xff & b);
                if (hex.length() == 1) hexString.append('0');
                hexString.append(hex);
            }
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return hexString.toString();
    }

    public static void addCookie(Account a) {
        try (FileOutputStream fos = new FileOutputStream("d://io//cookie.txt")) {
            fos.write(md5(a.username).getBytes());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void reg() {
        System.out.println("请输入你的账号");
        String account = sc.next();
        System.out.println("请输入你的密码");
        String password = sc.next();
        Account a = new Account(account, password);
        list.add(a);
        //存储集合
        //做序列化
    }

    public static void two(Account a) {
        System.out.println(a.username + "登录成功");
        while (true) {
            System.out.println("1.聊天功能");
            System.out.println("2.退出登录");
            System.out.println("0.返回上级");
            int n = sc.nextInt();
            switch (n) {
                case 1:
                    break;
                case 2:
                    break;
                case 0:
                    return;
            }
        }
    }
}

class Account {
    String username;
    String password;

    public Account(String username, String password) {
        this.username = username;
        this.password = password;
    }
}